New boiler/ Central heating system

Participant said:
Except when there's a power cut, under which circumstances an unvented cylinder merrily carries on about its business.

I've never had an acceptable electric shower.
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There is the thing it's all down to personal perception! We have an electric in our second bathroom as it was easier and cheaper to fit it doesn't get used very often as most people just jump in the combi boiler fed shower in the main bathroom which is much nicer but it's very handy for those odd occasions when two people want a shower at the same time. Our Electric shower has an inbuilt pump and is fed from a cold water tank in the loft which trickle fills so it has no impact on the other shower which to me made it perfect for an occasional use.
 
Just finished installing exactly what the OP is planning. Old system boiler, 3 loft tanks and vented cylinder in the airing cupboard removed.

Worc/Bosch Greenstar 27i boiler with NEST and OSO 210 litre unvented cylinder fitted in it's place.

A couple of towel rads replaced along the way as well, all fitted for £4500.

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More than happy with the system, nice hot powerful showers :)
loads of space cleared in the loft :)
NEST is busy learning at the moment so can't comment on that side of things yet but first impressions are great :)

main reason for upgrading was the boiler was a 17 year old Potterton (9kw) and was really struggling since we extended the property by 50% a few years back.

There's always debate about combi/system setups but each have their own benefits, for me the boiler needed to fit in the existing kitchen cupboard space, which a Combi wouldn't have. Another deciding factor was having 2 bathrooms and 2 teenagers who spend ages in the shower and I wanted to have no drop in pressure or temperature when running both showers.

yes it's more expensive and it's took a huge amount off our savings but those showers are worth it lol
 
M1k3H said:
Combination gas boilers still need electricity though
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Obviously :confused:. But with a full tank of hot water you can carrying on showering in the event of a power cut with an unvented system, was my point. Mentioning that combi showers need electricity when I'm comparing combi / electric showers to unvented hardly seems relevant.
 
it's a 210 litre tank

the average eight-minute shower used 62 litres of hot water, and some power showers can use up to 136 litres
stats taken from a quick google:
http://www.waterwise.org.uk/news.php/11/showers-vs.-baths-facts-figures-and-misconceptions

so looking at those averages 3 showers would empty the tank, or 2 depending on flow rate. which is pretty high in our house with anything over eco mode exfoliating skin lol.

I went with the 210 as it was a good fit for the airing cupboard along with the expansion tank, but what you've got to think is would NEST detect the water usage and thus call for hot water from the boiler prior to your houses surge on showers and thus steadily heat water to fill as you're using it. Mines scheduled for 2 hours from 6-8am and 3 hours in the evening from 5-8pm, probably because we mainly have showers in the evening.

We haven't once gone to the tap and found it cold so this schedule and capacity tank works for us.

Would you really all have a shower one after another every day?
 
why the need to replace the radiators?

reason i ask is. my home is also 20 years old (well 18). so i have a 20 year old boiler with tanks in loft and airing cupboard, etc.

i have zero plans to change the system. i have around 9 radiators. 2-3 of them are newer and around 6 of them are original so imperial.

the one in the living room has a duff bleeding valve so it leaks water. so it's turned off. i'm planning on replacing this only because it's broke. i'll be leaving all other radiators as is.

just wondering why people are replacing perfectly working radiators and boilers? makes zero sense. as for more loft space. well the tank will take up what 10% at most? why not just board the other 90%? if your not using it as a room makes zero sense to get rid of it.
 
I decided to replace my boiler, radiators, and pipework, as I had to move my boiler due to building an extension meant it was going to be in the middle of the house as opposed to venting externally.
Boiler and the rest of the system was probably 15+ years old, and having had to replace the pump last year and seen how choked up the pipes were (most of the runs were in micro bore pipe) I decided that as I was going to have to run some new pipes for the relocation of the boiler I'd replace them all and the rads to save pumping all the crud in the rads through my new boiler.
I also wanted to change the system design/ functionality which meant I would need to replace the pipework anyway.
 
Psycho Sonny said:
why the need to replace the radiators?

reason i ask is. my home is also 20 years old (well 18). so i have a 20 year old boiler with tanks in loft and airing cupboard, etc.

i have zero plans to change the system. i have around 9 radiators. 2-3 of them are newer and around 6 of them are original so imperial.

the one in the living room has a duff bleeding valve so it leaks water. so it's turned off. i'm planning on replacing this only because it's broke. i'll be leaving all other radiators as is.

just wondering why people are replacing perfectly working radiators and boilers? makes zero sense. as for more loft space. well the tank will take up what 10% at most? why not just board the other 90%? if your not using it as a room makes zero sense to get rid of it.
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I didn't replace rads when I fitted my sealed system boiler. It was open vent before so the pipes weren't under any pressure, all I did was go around and replace all the rad valves so i knew they were good. I was expecting to have to do some remedial work with leaks once it was pressurised but it has never given me any issues.

The reason I moved to a mains pressure sealed system was that I wanted to have good pressure for at least two showers and still fill sinks etc. I contemplated it on my old house but in the end went for a big combi boiler and was never very happy with it, so decided not to compromise this time.

One thing people often over look with mains pressure systems is the size of the inlet feed pipe to the house as you will only get as good flow as that can deliver. My last house was fed by 1"iron pipe and the inner bore was only around 15mm and my current house was fed with 15mm copper. I had a 25mm fitted on the last house and on this one changed the water pipe to a 32mm MDPE before I fitted the boiler.

The one thing I would change is that I fitted a 300L Valliant Uni-store tank to give me enough hot water in hindsight I would get the 210litre one as the recover time is so quick the reality is you wont run it out of hot water.
 
novaenough said:
I decided to replace my boiler, radiators, and pipework, as I had to move my boiler due to building an extension meant it was going to be in the middle of the house as opposed to venting externally.
Boiler and the rest of the system was probably 15+ years old, and having had to replace the pump last year and seen how choked up the pipes were (most of the runs were in micro bore pipe) I decided that as I was going to have to run some new pipes for the relocation of the boiler I'd replace them all and the rads to save pumping all the crud in the rads through my new boiler.
I also wanted to change the system design/ functionality which meant I would need to replace the pipework anyway.
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you can get a magnetic filter for all that stuff nowadays. in fact it's standard on all new builds as well as the newer systems.

as well for crud. don't you get rid of that when draining the system? can you not flush it through that way? also there shouldn't be much crud if inhibitor is used.

basically i'm wondering if i should replace all the old radiators or just the busted one. i've bought quite a nice designer one which wasn't cheap.
 
My rads are around 20 years old, all are showing signs of age and the TRVs are iffy. As boilers become more efficient and run your CH at a lower temp, and with needing replacing I took the opportunity to replace the radiators for largers ones so effectively I get the same wattage for heating but at a lower temp. Basically replacing for the next size up (not width or height) eg a single panel + single convector, with a double panel single convector.
 
I had my system powerflushed before I stripped the old system out. It's amazing the amount of crud it gets out of the system both magnetic and non magnetic. The pump was on the system for over 5 hrs with the acid running through the system.
 
Psycho Sonny said:
why the need to replace the radiators?

reason i ask is. my home is also 20 years old (well 18). so i have a 20 year old boiler with tanks in loft and airing cupboard, etc.

i have zero plans to change the system. i have around 9 radiators. 2-3 of them are newer and around 6 of them are original so imperial.

the one in the living room has a duff bleeding valve so it leaks water. so it's turned off. i'm planning on replacing this only because it's broke. i'll be leaving all other radiators as is.

just wondering why people are replacing perfectly working radiators and boilers? makes zero sense. as for more loft space. well the tank will take up what 10% at most? why not just board the other 90%? if your not using it as a room makes zero sense to get rid of it.
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I replaced all my radiators with much larger ones, for instance replaced a 1200x600 type 10 with a 1800x600 type 21. Did similar in each room sizing the radiators for a Delta temperature of 35c. Old boilers didn't condense so the need for low flow temperatures wasn't needed, they were also sized around a much higher Delta , a condensing boiler with old undersized radiators probably won't condense much.
Mine typically runs with a temp of around 35c to keep the house warm, so definitely condensing.

Plus all ours were covered in many years worth of paint. Changing the pipes because it was a full 1/2" system and needed converting to a 22mm / 15mm system, routing the pipes better in the wall instead of boxed in.
They were also noisy often vibrating against joists and floor boards, changed the lot to plastic. Silent now.
 
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A mag filter certainly should be fitted but I'm pretty sure there's no requirement.
A house builder will be thinking thats £30 they don't really need to spend.
 
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